a. tayebi

Training of athletes can be quantified by training load. In recent years, the concept of training load has received more attention, and this is important because the necessity of monitoring the athlete in line with the required adaptations of the desired sport's needs is of great importance. Therefore, studies considering the relationship between training load and the risk of injury and overtraining are more emphasized. The purpose of the present study is to answer the question of whether it is possible to prevent injuries by controlling the exercise load?

Articles were searched in the PubMed Medline and Science direct and Google scholar  database and keywords injury, exercise load, and combination of words Injury& Prediction and  Load & Injury 2016 and 2022. Only experimental and semi-experimental studies were reviewed.

A total of 25 articles were selected among 507 studies based on the inclusion criteria. Most of the reviewed studies introduced the ACWR criterion as an important criterion in measuring training load and reported its relationship as an injury risk factor. These studies investigated the relationship between training and competition load and athletes' injuries. The results of the reviewed studies showed that the ACWR criterion is an important criterion in measuring the training load and this criterion is introduced as an injury risk factor.

Results of the present study showed training load is related to the possibility of injury in athletes, but there is still a debate in scientific circles about the exact way of this relationship. Additionally, the best way to measure load training is the measurement of internal and external load together. Results also illustrated that the pattern of impact of training load on the probability of injury in athletes in individual and team sports is different.  In order to consider the principle of individual differences in the probability of injury, it is necessary to use criteria that can report the internal load of each athlete individually.

Energy harvesting is the process of converting different kinds of energy, such as solar, thermal, kinetic energy of fluid, etc., to a usable form of energy. Different kinds of transduction mechanisms are used for energy harvesting. The piezoelectric mechanism has received considerable interest because of its advantages, such as ease of application and working over a wide range of frequencies. Simulation and investigation of energy harvesting from a piezoelectric plate, which is mounted on an elastic beam and located behind a cylinder through flow-induced vibrations, is the subject of the present research. First, the results of the lift and drag coefficients in the fluid flow around a stationary cylinder at Reynolds 200 are compared and validated with the previous studies. After that, by placing an elastic beam and a piezoelectric behind the cylinder, flow around the cylinder, and the fluid-solids interactions are investigated. Due to the vortex shedding phenomenon, which happens in the fluid flow past the cylinder, the elastic piezoelectric beam deforms periodically, and thus, the mechanical energy of the flow is converted into electrical energy. In this problem, the beam effect on both the drag/lift reduction and the amount of voltage extracted from the piezoelectric layer were investigated, and the optimal mode obtained was selected based on the extraction of more energy. In this regard, the process of finding the most optimal energy harvesting mode for the location of the elastic beam, the length of the beam, and the fixed point of the elastic beam in different geometries are carried out. The results of the optimal investigations are as the length of the elastic beam of 2D, the distance of the beam from the back of the cylinder 2.5D, and the state in which the beam is fixed from the right side, where D is the diameter of the cylinder.

Design and simulation of high directive waveguide directional couplers based on supershapes are presented, in the present paper. In order to obtain high directivity, circular holes in a conventional coupler are equivalently substituted with supershape holes. In the frequency range from 8 to 12 GHz, the coupling values of two proposed couplers are 19±1 dB and 23±2 dB and the directivities are better than 20 dB. The simulation results show that almost 20 dB improvement in the directivity can be achieved as compared to a conventional coupler. The results are valuable for the design and development of broadband high directive waveguide couplers.